Material

Glass

Acrylic

Cost

Glass is cheaper since it is more popular. They are also easier to ship since they are very hard to scratch and have a better impact force. So glass tanks tend to be less expensive than acrylic tanks.

Acrylic tanks tend to be more expensive than glass tanks. Although acrylic as a material is cheaper to manufacturer and transport glass is still cheaper. In many cases it will cost less to make the acrylic tank, but after a few break due to it being easily scratched and low impact needed to break the cost to the aquarium owner is much higher than the glass tank.

Scratching

Very difficult to scratch, This is the main reason why we recommend glass as a first tank.

Super easy to scratch. You will have to be extra careful, use acrylic safe algae scrubbers and acrylic polishing kits. But do you really need more chores?

Weight

Glass is heavier than acrylic. A glass tank will often weigh as much as 10 times as much as an acrylic tank of the same volume. A small acrylic aquarium is much easier to lift than a glass one, even with water inside.

Acrylic tanks are lighter than glass tanks. A small acrylic aquarium is much easier to lift than a glass one. You can easily move the tank around your home even with water inside.

Shapes

Not too many shape options. The hard, brittle nature of glass makes it difficult to shape. This is why most glass fish tanks are square or rectangular. Also, curved glass aquariums have the tendency to bend light, making the fish on the inside appear larger or smaller than they really are.

Acrylic is easily molded and can be formed into almost any shape. Acrylic also bends light less which means it won’t distort things that are behind the glass and your fish will look how they should.

Impact resistance

A sharp impact will crack or shatter a glass tank, or at least one of its sides. However, the force required to break a glass tank needs to be pretty significant. Better off choosing a different location for your fish tank.

Acrylic is much more resistant, though a very sharp impact will crack or shatter a piece of acrylic, the amount of force needed for this damage is far greater than it is with a glass tank.

Clarity

Glass maintains its clarity over time. The glass does not suffer from the same problem like acrylic (Becoming cloudy) and will remain clear.

Many types of acrylic will yellow with age, particularly if they are kept under a full spectrum light or are exposed to direct sunlight. While there are “UV-resistant” acrylic aquariums, eventually they discolor. Also, because the acrylic is so fragile, it is very likely that you will be viewing your fish through a haze of scratches that will only get worse over time.

Workability

Less modifiable. Less creative projects you can do with glass. Although you can still drill a hole through glass it is a nerve-racking experience.

Easily modifiable. If you love DIY projects then acrylic is the way to go. You can easily drill holes to make way for pump outlets, overflows and anything creative you can think of.

Support

Glass aquariums can be kept on stands with an open or incomplete top with little or no risk since glass can support considerably more than its own weight over distances.

Acrylic tanks require a stand that will support the entire bottom of the tank, or else the bottom of the tank may pull away from the seams under the weight of the water. This is not true in acrylic tanks that have a substantially thicker bottom than would appear necessary. Also, acrylic tanks require much more support across the top of the tank to keep the acrylic from bowing apart and either splitting seams or spilling water.